12 * September 19 - Mark Braunstein, WA4KFZ, provided an overview of printed circuit board fabrication for the electronics experimenter. Mark has personal experience using CNC routers in a commercial enterprise. Other options for do-it-yourselfers include conventional photo-etching and contact etching with laser printed masks. A number of domestic and foreign fabricators offer fast turn around at low cost but with confusing choices for software and file formats.

14 * August 8, 2013 - Maitland Bottoms, AA4HS, introduced us to digital voice communications on HF using FreeDV software. FreeDV is an application for Windows, Linux and MacOS (BSD and Android are in development) that allows any SSB radio to be used for low bit rate digital voice.

15 The software compresses speech to 1400 bit/s then modulates a 1.1 kHz wide quadrature phase-shift keying (16-QPSK) signal which is sent to the Mic input of a SSB radio. On receive, the signal is received by the SSB radio, then demodulated and decoded by FreeDV. Communications is readable down to 2 dB S/N, and long-distance contacts are reported using 1-2 watts power.

18 FreeDV is unique as it uses 100% Open Source Software, including the audio codec. FreeDV represents a path for 21st century Amateur Radio where Hams are free to experiment and innovate without being locked into a single manufacturer’s proprietary technology.

20 The same cables and hardware that you use for other digital modes that are based on PC programs will work with FreeDV, but you will need a second sound interface for the microphone and speaker connections to the FreeDV program. A USB headset of the sort used by gamers is all you need for the second sound interface.</P></blockquote>

22 * July 18, 2013 Dr. Frank Eliot, W3WAG, discussed Weak Signal Detection. Thanks to the rapid increase in digital processing availability, hams have implemented sophisticated and user-friendly techniques that enable us to communicate with much weaker signals than we had dreamed of exploiting just a few years ago. In this session, Frank discussed weak signal detection, exploring under what circumstances we might detect even weaker signals, thus communicating over even more difficult paths. Also, on a related topic, he described how earth antennas behave, and experiments one might perform to sort out their modes of operation.